The effect of unilateral testicular torsion on the contralateral testis and the fertility rate was studied in Charles River adult rats. Animals were divided into groups that underwent a sham operation or torsion and ligation of the left testicular vessels followed by orchiectomy after 24 h, orchiectomy after 48 h, release of the ligature after 24 h, release of the ligature after 48 h, and no further treatment following ligation. Another group of animals underwent unilateral orchiectomy. After 8 weeks animals were allowed to mate and were sacrificed 2 weeks later. The results did not point to either histological alterations in the contralateral testis or impairment of fertility in any group of treatment compared with the control.